This,
Myriad is the most secure coin at the moment even if we can't really prove it yet.

X11 is just famous, most of peoples voting for it have even not idea of how it works exactly. X11 is good for the short/medium term only, like Scrypt was. But as soon as this will be "bypassed" by miners, all the coins using this algo will have sever issue.

The thing with multi-algo is each algo have it own difficulty, so even if the scrypt getting mined as hell, this is protected by the other algo.

I'm using absolutely fictive numbers,
but let say you have 2 miners on Skein on a low difficulty, and 400 miners on Scrypt, pushing the Scrypt to high difficulty. It will easier for the 2 dudes on Skein to find the next block, screwing the Scrypt miners, even if they throw out a incredible hashrate.

So this system is absolutely not a hashrate race, but an algo race.